Apparatus for the manufacture of a tubular container sleeve

ABSTRACT

In apparatus for manufacturing tubular container sleeves, a blank is wrapped around a fixed mandrel by means of a pair of sweeper arms that are swingable and movable in translation. In each sleeve forming operation the sweeper arms are displaced from a position in which both are wholly at one side of the mandrel to a position in which they embrace the mandrel, each having an inner pivoted end at that one side of the mandrel and an outer swinging end at the other side of the mandrel. During at least the final half of each such displacement the outer ends of the sweeper arms maintain constant engagement against the mandrel through the blank. During the first half of that displacement the blank is progressively engaged against the mandrel by a sweeper band extending under tension between the outer ends of the sweeper arms.

The present invention generally relates to the manufacture ofcontainers, and the invention is more particularly directed to anapparatus for the manufacture of tubular container sleeves from a planeblank of cardboard, plastic, sheet metal, a thin laminated material or asimilar material.

In the manufacture of certain types of containers, especially containersof rounded shapes such as containers having rounded corners or having acircular, elliptical or similar cross section, it has been customery tomake a container sleeve which is closed at one end and which is filledwith the material to be packed and thereafter closed at the oppositeend.

The container sleeve can be manufactured in several different ways. Thesleeve can be made by sprayforming or dieforming a plastic material orby winding a material spirally onto a mandrel whereafter the tube may becut at the ends to a suitable length. This is a timeconsuming methodwhich is not suitable for use in direct connection with the filling andthe closing of the container, and the premanufactured container sleevesare bulky, and in many cases the container sleeves must be sterilizedbefore being filled with the material to be packed. The latter methodalso gives a container which for many types of goods is not sufficientlyliquid- and gasproof. Therefore there is a wish that the containersleeve be made in direct connection with the filling and the closing ofthe container, whereby the container sleeve should be made from a planeblank of cardboard, plastic, any laminated material, sheet metal or asimilar material.

The formation of a container sleeve having rounded form, for instancerounded corners or having a circular, elliptical or otherwise roundedcross-section, causes some problems which are directly dependent on thefact that the container sleeve must have a carefully calculated innersize so that the bottom and top closures can be connected to thecontainer sleeve to provide a wellsealed container. This is especiallyimportant in containers having inner bottom and top closures.

Several different methods are known in the art for making a containersleeve from a plane blank of cardboard or a similar material.

The German patent DE No. 29 28 773 discloses a method in which thesleeve is made inside an outer fixed mandrel by means of presssemicylinders acting from inside the sleeve and thereafter possibly bymeans of concave press rollers acting from outside. This method istimeconsuming, expensive and complicated, the method is limited to aspecific type and size of container and there are great demands on thefitting dimensions between the outer mandrel and the inner presssemicylinders.

Therefore it is to preferred that the sleeve is formed from outside onan inner fixed mandrel, and such an outer formation method is disclosedin U.S. Pat. No. 4,349,345. The patent discusses the problems of havingthe container blank carefully fit and follow the mandrel at the roundedcorners, and in this patent the formation problems have been solved bymeans of outer fixed formation jaws which at the upper rounded cornersof the container provide a special compression of the corners by meansof rotatably mounted wings. Also this apparatus is disadvantageous inthat the method is limited to a specific type and size of the containersleeve and that it is important that the inner mandrel and the outerjaws carefully fit each other and the method is relatively slow, and thecosts for the mandrel and the jaws are relatively high.

The German laid open publication DOS No. 23 05 702 discloses a method inwhich a container sleeve is made on a fixed inner mandrel by means of anelastic ribbon acting between two rotatable arms. Since the tension ofthe elastic ribbon is increasing as the arms are folded up and round thefixed mandrel the tension of the folding or sweeping ribbon is stronglychanged during the formation and this may lead to stretchings andtensions in the container blank so that the container sleeve afterhaving been removed from the mandrel may shrink or wrinkle or may beotherwise deformed.

The German laid open publication DOS No. 29 06 592 discloses analternative method using a non-elastic sweeping band which is keptstretched by a tension spring operating between the band ends and inwhich a pair of rotatable arms are adapted to fold the band togetherwith the sleeve blank round a fixed inner mandrel. In the sweepingprocess the arms are rotated about fixed shafts in relation to themandrel. Also in this apparatus stretchings or tensions may betransmitted from the band to the container blank in that the band endsare freely connected to each other through a tension spring so that theband can move on the rotatable arms during the entire sweeping movement.When the sleeve blank is swept round the mandrel quantities of air maybe enclosed which can not be pressed out by the spring loaded band.

All described apparatus are disadvantageous in that they only allow themanufacture of sleeves having a specific shape and size and in thatother shapes or sizes of sleeves can be made only after a substantialrebuilding of the machine.

The object of the invention therefore is to solve the problem ofproviding an apparatus of the above mentioned type in which the sleeveblank is carefully conformed to the inner mandrel without the risk ofstretchings and tensions of the blank and without the risk thatquantities of air will be enclosed between the sleeve blank and themandrel and without the risk that the finished container sleeve willwrinkle or be subjected to tensions. A further object of the inventionis to provide an apparatus for the manufacture of a container sleevewhich apparatus may quickly and simply be readjusted for the manufactureof sleeves having different shapes and different sizes, especially byreplacing the inner mandrel and simply readjusting the scheme ofmovement for the available sweeping arms.

Therefore the invention relates to an apparatus for the manufacture oftubular container sleeves having rounded shapes and made of cardboard,plastic, sheet metal, any laminated material etc. from a plane sleeveblank and comprising a fixed mandrel around which the sleeve blank isintended to be swept and sealed to an integral container sleeve, twosweeping arms over which a spring loaded sweeping band extends, andmeans for rotating the sweeping arms together with the plane sleeveblank round the mandrel, and means for securing the sleeve blank in thesleeve shape thereby provided.

The most characterizing part of the invention is that the sweeping armstogether with their swinging axes are displaceable in relation to themandrel at the same time as they are rotated about their shafts so thatthe free ends of the arms during the sweeping operation slide along orclose to the mandrel while successively pressing the sleeve blank to themandrel. The successive displacement of the ends of the sweeping armsover the mandrel may be started anywhere from the line where the sleeveblank gets into contact with the mandrel to a line located at somedistance therefrom, but usually it is sufficient that the contactbetween the arm ends and the mandrel is started from a place at or closeto the central line of the mandrel.

In a preferred embodiment of the invention the sweeping arms arepositively guided in their movement by means of guide grooves, wherebyany wanted container shape can be obtained.

By a simple readjustment of the length of stroke and the sweepingmovement for the sweeping arms and a simple exchange of mandrel theapparatus according to the invention can easily be adapted to themanufacture of container sleeve of different sizes and different shapes.

Further characteristics of the invention will be evident from thefollowing detailed description in which reference will be made to theaccompanying drawings.

It is, however, to be understood that the illustrated and describedembodiments of the invention are only illustrating examples and thatmany different modifications may be presented within the scope of theappended claims.

In the drawings FIG. 1 is a vertical cross section through an apparatusaccording to the invention in a position for sweeping a sleeve blankround a fixed mandrel. FIG. 2 correspondingly shows the apparatus afterthe sweeping operation is completed and in a position for sealing thecontainer sleeve. FIG. 3 is a cross section in a side view of theapparatus of FIG. 1, seen along line III--III. FIG. 4 is a verticalcross section through an alternative embodiment of the apparatusaccording to the invention, and FIG. 5 is a top view of the apparatusaccording to FIG. 4.

The apparatus shown in FIGS. 1 and 2 generally comprises a carrier 1 fora plane sleeve blank, a fixed mandrel 2 on which a sleeve blank isadapted to be formed to an integral container sleeve, a pair of sweepingarms 3, a means 4 for raising and lowering the sweeping arms and a means5 for rotating the sweeping arms.

The carrier 1 for the sleeve blank is in the form of a pair of rails 6which are fixedly mounted in the machine and along which a plane sleeveblank 7 is fed from alongside the sleeve forming apparatus and in theactual direction of the mandrel 2. The rails 6 are provided on oppositesides of the mandrel and so as to allow a free movement upwards anddownwards respectively of the sweeping arms 3.

The mandrel 2 is likewise fixedly mounted in a machine support (notshown) and in a position between the rails 6 and above the sweepingarms. The mandrel 2 may have very varied shape, for instance oval,elliptical, circular, polygonal with rounded corners etc. and it mayeven be conical in the actual direction. The most usual form and theform which is most simple to handle, however, is thecircular-cylindrical form. The mandrel preferably is mounted so that itcan easily be removed, whereby a mandrel of a specific shape and sizecan be substituted for a mandrel having another shape or another size.

The sweeping arms 3 are mounted symmetrically with reference to thelongitudinal axis of the mandrel 2 and so that the arms can be moved upand down at the same time as the arms are rotated between an open downposition which is shown in FIG. 1 and a closed upright position which isshown in FIG. 2. Each sweeping arm 8 is mounted for rotation on arotatable shaft 9 in a carrier 10 which is vertically displaceable ontwo guide bars 11 of the machine support. The swinging shafts 9 arerotatably mounted in the carrier 10. An actuation bar 12 is fixed toeach swinging shaft 9 for providing a swinging movement of the sweeperarms 8 upon actuation.

The carrier 10 is connected to an actuation arm 14 through a link 13,and by means not shown in the drawings said actuation arm 14 is adaptedto move vertically up and down in relation to the fixed mandrel 2, tomove towards and from the mandrel at its underside through a distancewhich is at least equal to the diameter of the mandrel. Each actuationbar 12 which is fixedly mounted on a swinging shaft 9 for a sweeper arm8 is at its outer end formed with a guide roller 15 which is slideablein a guide block 16 having guide grooves 17. The guide block 16 isfixedly mounted in the machine support. Each guide groove 16 and itscooperating guide roller 15 thus comprise cooperating fixed and movableguide elements, there being a fixed and a movable guide element for eachsweeping arm 8 of which the fixed guide element 16 is stationary withrespect to the mandrel while the movable guide element 15 is spaced fromthe axis of the swinging shaft 9 about which its sweeping arm swings andis so connected with its sweeping arm 8 as to constrain that sweepingarm to swing about that axis with it. Of the pair of cooperating guideelements 15, 16 for each sweeping arm, one has a curving edge portionwhich is at all times slidingly engaged by the other as the carrier 10moves towards and from the mandrel 2 to thus control the positions ofswinging of the outer ends 18 of the sweeping arms as the shafts 9 aretranslated towards and from the mandrel. As here shown, said curvingedge portion is on the fixed guide element 15 and is defined by itsguide groove 17. The form of the guide groove depends on the form andsize of the mandrel 2 and the groove is formed so that the outer ends ofthe sweeper arms 8 move closely along or press the sleeve blank 7lightly to the mandrel 2 at least during a part of the sweepingmovement. The guide grooves which thereby provide a positive guidemovement of the sweeper arms 8 always should be formed so that the ends18 of the sweeper arms 8 at the final point of the sweeping movement arelocated close to each other at the upper side of the mandrel 2. In casethe sleeve is joined by a lap joint or by means of a joining stripprovided along the inner surface of the sleeve the guide grooves 17further should be formed so that the inner part of the lap joint or thesleeve blank edge bearing the joining strip, respectively, is alwayspressed to the mandrel before the other sleeve blank edge.

In the right hand part of FIG. 1 the form of a guide groove 17a isdiagrammatically illustrated that provides a pressing of the sleeveblank 7 from a line substantially corresponding to the center of thecylindrical mandrel 12. It is evident that a first part (the lower part)of the groove extends vertically whereas the groove at the end of themovement upwards of the sweeper arms 8 is bowformed so that the outerends 18 of the sweeper arms exactly follow the outer surface of themandrel.

In the lefthand part of FIG. 1 a guide groove 17b is likewisediagrammatically illustrated which groove is bowformed so that the outerends 18 of the sweeper arms 8 move close to or are pressed to themandrel 2 from a point adjacent the lower side of the mandrel as far asto a point adjacent the upper most surface of the mandrel.

It is obvious that the sweeper arms may be brought to move along anyactuation path by changing the form of the guide grooves 17. By furtherchanging the stroke for the vertical displacement of the actuation arm14 of the carrier 10 it is also possible to change the length of thevertical displacement. By two simple operations it is thereby possibleto carefully adapt the movement of the outer ends 18 of the sweeper arms8 to a mandrel 2 having different form and size. In FIG. 1 the referencenumeral 19 indicates the smallest size of a mandrel for which thespecific apparatus shown in the drawings has been adapted.

The sweeper arms 8 cooperate with a sweeper band 20 for sweeping acontainer blank 7 round the mandrel. Each outer end of the sweeper band20 is mounted in a spring arm 21 intended to keep the band stretched inall positions of the sweeper arms 8. Each spring arm 21 is rotatablymounted on the swinging shaft 9 for the sweeper arm 8, and the springarms 21 are actuated in the direction outwards-downwards by tensionsprings 22. The sweeper band 20 extends from the ends of the spring arms21 over a roller 23 at the end of each sweeper arm 8 and provides acontinuous sling between the spring arms. The central point of thesweeper band 20 is mounted in a fixed press device so that the band 20can not be displaced in relation to the mandrel and the sleeve blankwhile sweeping said sleeve blank round the mandrel.

The press device comprises a press arm 24 which is mounted on arotatable pin 25 and which at the top has a press-body 26 providing apress locking of a container sleeve 7 to the mandrel 2 when the pin 25is rotated with the arm 24. Thereby a displacement of the blank inrelation to the mandrel is prevented during the sweeping operation. Aspreviously mentioned the sweeper band 20 is mounted in the press-body 26for preventing a displacement of the band in one direction or the otherin connection with the sweeping operation.

For joining of the sleeve blank 7 after it has been swept round themandrel the apparatus includes a sealing block 27 provided above themandrel and movable between an upper position in which the sleeve blankcan be freely swept round the mandrel 2 and a lower position in whichthe sealing block 27 presses the sleeve blank to the mandrel. Thesealing block may be a heated block which by constant heat, highfrequency heat or ultrasonic heat provides a weldjoining of the sleeveblank edges, or it may be a cold press block which by means of apressure sticking glue joins the two edges of the sleeve blank.Preferably the sleeve blank is formed with a weldable material like aweldable plastic material at one or both edges, and said weldablematerial makes it possible to join the two edges of the sleeve by asimple overlap weldjoint. In a preferred embodiment the sleeve blank isat one end formed with a projecting weldable strip attached to the innersurface of the sleeve to be formed. By means of said weldable strip thesleeve can be joined edge to edge (butt joint).

The apparatus shown in FIGS. 4 and 5 differs from the above describedapparatus mainly in that the two sweeper arms are mounted on a commonshaft 9'. Otherwise the apparatus works in the same way as thepreviously described apparatus.

The function of the appatratus is as follows;

The starting position of the apparatus is shown in FIG. 1, in which thesweeper arms 8 are located in their lower positions and the press device24, 26 is retracted from the mandrel 2. Depending on the form of theguide grooves 17a or 17b the sweeper arms 8 take the position shown inthe right hand part or the left hand part respectively of FIG. 1. Asleeve blank 7 is fed to a position underneath the mandrel 8 and is keptin a predetermined position by the carrier rails 6. The press device 24,26 is rotated to its upper position together with the band which isfixedly mounted thereon, whereby the pressblock 26 together with theband presses the sleeve blank 7 against the mandrel 2. Thereafter theactuation arm 14 is moved up so that the link 13 and the carrier 10together with the sweeper arms 8 are moved upwards. Depending on theform of the guide grooves 17 the sweeper arms 8 are moved according to apredetermined path while being moved upwards, and the sweeper band 20sweeps the container blank 7 round the mandrel 2. In the caseillustrated in the right hand part of FIG. 1 the ends 18 of the sweeperarms do not get in contact with the mandrel 2 until at a linesubstantially at the center of the mandrel, in the left hand case ofFIG. 1 the ends 18 of the sweeper arms get into contact with the mandrelalready adjacent the bottom surface thereof. Of course the two sweeperarms 8 should be actuated by mirror symmetrical guide grooves 17 so thatsaid arms obtain substantially the same scheme of movement. Aspreviously mentioned, however, one edge of the sleeve blank should bemoved slightly in advance of the other edge, so that the edges to bejoined are located over each other. This is important whether the jointis made as an overlap joint or an edge to edge butt joint by means of aninner joining strip. The guide blocks 16 with the guide grooves 17should be adjusted so that the sweeper arms 8 with a slight pressurekeep the container blank pressed to the mandrel 2. When the containerblank is completely swept round the mandrel and the joining edges havebeen put over each other the sealing block is moved down and the blankis joined to provide a sealing unit. After the different parts of theapparatus have returned to their starting positions the container sleeveis released from the mandrel and is formed with bottom, is filled and issealed with a top closure.

When changing the form and size of sleeve the mandrel is exchanged foranother mandrel and the stroke of the link 13 and the adjustments of theguide blocks 16 are adjusted in accordance with the new mandrel. If theform of the sleeve is changed it may be necessary to substitute theguide blocks for guide blocks having another form of the guide grooves17.

I claim:
 1. Apparatus for the manufacture of tubular container sleeves, each having a rounded cross-section and formed from an initially flat blank of sheet material that has a pair of opposite edge portions, said apparatus comprising a fixed mandrel which has a mandrel axis between a pair of opposite sides thereof and which has said cross-section and is thus adapted to have a blank swept therearound to be formed to said cross-section with its said edge portions adjacent to one another over one of said sides of the mandrel, sealing means at said one side of the mandrel movable towards and from the mandrel for clampwise cooperation with it whereby said edge portions of a blank wrapped around the mandrel are sealed to one another, and a pair of sweeper arms for sweeping a blank around the mandrel, each having an inner end and an outer end, said apparatus being characterized by:(A) a carrier at the other of said opposite sides of the mandrel, confined to motion in opposite directions towards and from the mandrel through a distance at least equal to the diameter of the mandrel; (B) shaft means on said carrier, constrained to motion in said opposite directions therewith and to which each sweeper arm is connected at its inner end, said shaft means defining for each sweeper arm a swinging axis parallel to said mandrel axis that is adjacent to the inner end of the sweeper arm and about which its outer end swings while the sweeper arm moves with the carrier through said distance to have its outer end carried to and from each of said sides of the mandrel; (C) cooperating fixed and movable guide elements for each sweeper arm,(1) the fixed guide element being fixed in relation to the mandrel, (2) the movable guide element being spaced from the swinging axis of its sweeper arm and having a connection with its sweeper arm whereby the latter is constrained to swing about its swinging axis in unison with movement of the movable guide element about that axis, and (3) one of said guide elements having an edge portion which is at all times engaged by the other guide element as the carrier moves in said directions and which is so curved that during substantially the final half of the movement of the outer end of the sweeper arm from said other side of the mandrel to said one side thereof said outer end maintains constant engagement, through a blank, against the surface of the mandrel to press successive portions of the blank into contact with the mandrel; and (D) a sweeper band trained around the outer ends of the sweeper arms and having a portion extending between those outer ends under yielding tension to engage a blank and press successive portions of it into contact with the mandrel as the carrier moves in the direction towards the mandrel through substantially the first half of said distance.
 2. The apparatus of claim 1 wherein said sweeper band is substantially inelastic and has opposite end portions, further characterized by:sweeper band biasing means connected between each end portion of the sweeper band and said shaft means to maintain the sweeper band under lengthwise tension with its end portions extending away from the outer ends of the sweeper arms and the mandrel.
 3. The apparatus of claim 2 wherein said sweeper band biasing means comprises:(1) a spring arm for each sweeper arm, each spring arm having an inner end connected with said shaft means to be swingable about the same and having an outer end connected to an end portion of the sweeper band; and (2) a spring connected to the outer end of each spring arm to bias the same for swinging away from the mandrel.
 4. The apparatus of claim 2, further characterized by:a press device to which the sweeper band is fixed at a point on the sweeper band that is between the outer ends of the sweeper arms, said press device being movable toward and from engagement with the mandrel at said one side thereof. 